Heihe is a prefecture-level city of northern Heilongjiang province, China, located on the Russian border, on the south bank of the Amur River, across the river from Blagoveshchensk. At the 2020 census, 1,286,401 people lived in the prefecture-level city of whom 223,832 lived in the built-up area made of Aihui District. Heihe marks the northeast terminus of the diagonal Heihe–Tengchong Line, which is sometimes used to divide China into east and west.